Images in Cardiovascular Medicine Zero-Contrast Thoracic Endovascular Aortic Repair Using Image Fusion

In recent years, thoracic endovascular aortic repair (TEVAR) has been established as a reliable alternative to conventional surgical repair.1 The success of endovascular repair is critically dependent on adequate stent-graft deployment. Catheter-based 2-dimensional angiography is routinely performed before, during, and after stent-graft placement to ensure accurate positioning and confirm the absence of complications such as perigraft endoleaks. Computed tomography angiography (CTA) is also used to plan stent-graft deployment before intervention. Recent advances in imaging technology allow reusing the diagnostic volumetric data sets during intervention by overlying live fluoroscopy over the preacquired CTA.2 This article describes the first case of TEVAR under guidance of CTA superimposed on live fluoroscopy without the use of iodinated contrast agent before, during, and after deployment. An 82-year-old man was admitted to the hospital with an asymptomatic thoracic aneurysm of 65-mm diameter on the descending aorta extending from 85 mm below the left subclavian artery to 120 mm above the celiac trunk (Figure 1). Ten years earlier, the patient had undergone surgical repair of an abdominal aortic aneurysm. No other comorbidities existed. Given the age of the patient, he was scheduled for endovascular treatment with a thoracic aortic stent graft. Endovascular navigation and stent-graft deployment were achieved using superimposition of preacquired volumetric CTA data on live 2-dimensional fluoroscopy (MR/CT Roadmap, Philips Healthcare, Best, the Netherlands). The CTA was acquired 1 hour before the patient was transferred to the interventional suite for placement of the thoracic stent graft. For registration of the live fluoroscopy with the CTA volume, a low-dose cone-beam CT acquisition (XperCT, Philips Healthcare) without injection of iodinated contrast was acquired after induction of general anesthesia and before draping the patient. During patient preparation, the preacquired CTA volume was fused with the intraoperative conebeam CT. This has the effect of bringing the CTA volume into the same coordinate space as the live fluoroscopy, thus allowing fluoroscopic navigation over the diagnostic CTA.2 Under guidance of the CT roadmap, the thoracic aortic stent graft (Valiant, Medtronic, Minneapolis, MN) was inserted through the right common femoral artery, positioned to cover the aneurysm, and deployed into the descending thoracic aorta (Figure 2 and online-only Data Supplement Movie). A transesophageal echography transducer introduced at the level of the aneurysm was used as a second control and to detect possible complications, particularly endoleaks. The stent graft used was 155-mm long and had a 46-mm proximal diameter and a 42-mm distal diameter. After deployment, a final cone-beam CT scan without contrast was acquired to confirm complete aneurysm coverage by the stent graft (Figure 3). Transesophageal echography control showed no complications. The procedure time was 20 minutes, with 7 minutes of fluoroscopy time. The radiation dose measured by the dose area product was 55.3 Gy cm. Three days later, the patient was discharged from the hospital with no postinterFigure 1. Pretreatment contrast-enhanced CT showing a thrombotic aneurysm in the thoracic aorta (yellow arrow).